This invention relates to a method for improving reliability of a file server, and more particularly, to a method for accelerating a memory test of a large-capacity memory upon system boot up.
The recent increase in amount of data stored in companies, research facilities, and other organizations has created a demand for a high-performance file server which stores data in a network, and is causing a memory installed in a file server to have larger capacity. In order to improve the reliability of a file server, a high-precision memory test is desirably conducted each time the system boots up, and hence a memory error is detected in advance. Conducting a high-precision memory test, however, involves reading and writing a plurality of test patterns from and to the memory medium, and a problem is that the time required for the memory test increases linearly as the memory capacity increases.
As a solution to this problem, a method has been disclosed in which a memory test is conducted upon system boot up only on an area used to start up the OS, and a memory test for the rest area is performed in the background after the start up (see U.S. Pat. No. 5,155,844, for example).
According to the prior art where the file server tests only a memory area that is necessary to start up the OS upon system boot up, the OS can be started up within a fixed period of time, irrespective of the capacity of the installed memory.
However, in order for the file server to be able to provide a file service immediately after system boot up, a memory capacity necessary for the file service has to be secured in addition to the memory capacity necessary for the OS startup. When the file server starts providing a file service without securing the necessary memory capacity first, evacuation of stored data from the memory to a disk can cause a significant drop in system performance or memory exhaustion can bring the system down.
There has been no existing technique that can adequately estimate the memory capacity necessary to provide a file service. Estimating the necessary memory capacity adequately is particularly difficult with file servers because the count and capacity of managed file systems differ from one file server running environment to another, and the memory capacity usage varies depending on whether there is an optional program for improving the reliability and the usability in data backup and other operations.